Holtec International's SMR-300 small modular reactor design has completed the first step of the UK's Generic Design Assessment process and progressed to the next phase of its assessment.

Holtec's image of a two-unit SMR-300 plant (Image: Holtec)

Generic Design Assessment (GDA) is a process carried out by the Office for Nuclear Regulation (ONR), the Environment Agency and Natural Resources Wales (NRW) to assess the safety, security, and environmental protection aspects of a nuclear power plant design that is intended to be deployed in Great Britain. The GDA process is a voluntary, non-mandatory process. Successful completion of the three-step GDA culminates in the issue of a Design Acceptance Confirmation (DAC) from the ONR and a Statement of Design Acceptability (SoDA) from the Environment Agency.

In May 2021, the UK's Department for Business, Energy and Industrial Strategy opened the GDA process to advanced nuclear technologies, including SMRs.

Step 1 of the GDA of Holtec's SMR-300 began in October 2023 and focused on agreeing the scope and schedule for Step 2. This stage has now been successfully completed.

"Holtec has completed all the requirements for Step 1 from the regulators' guidance with good progress made in developing its organisation and arrangements to support GDA," ONR said. "Today marks the start of the fundamental assessment of the design (Step 2) which is expected to last for 14 months."

As Holtec is undergoing a two-step GDA for its SMR-300 design, no DAC or SoDA will be issued and the regulators' assessment will stop at the end of Step 2. At the end of Step 2 the regulators will issue a GDA Statement, indicating their level of confidence in whether the SMR-300 design can potentially be built, operated and decommissioned in Great Britain in a manner that is safe and secure. Should Holtec wish to continue its plans to build an SMR in England or Wales, a further period of detailed design assessment will be carried out by the regulators, either as part of a future Step 3 or as part of a site-specific development.

Holtec has now launched a comments process, enabling anyone to submit comments and questions about the reactor design to the company for its response. Relevant issues raised during the comments process, and Holtec's responses to these issues, will be used to help inform the regulators' assessments throughout the rest of the GDA process.

Environment Agency New Reactors Programme Manager Saffron Price-Finnerty commented: "This is a two-step GDA which won't include a scheduled public consultation, so it's even more important for people to get involved in the comments process."

Holtec has been developing its SMR unit since 2011. The SMR-300 is a pressurised water reactor producing around 300 MW of electrical power or 1050 MW of thermal power for process applications, and the company says it has undergone several design evolutions, the most recent of which is the incorporation of forced flow capability overlayed on gravity-driven flow in the plant's primary system.

Holtec welcomed the completion of Step 1 in the GDA process for its SMR "in a mere 10 months". It added: "This approval speaks to the high confidence of UK regulators in SMR-300 and their commitment to prioritise introduction of new nuclear reactor technologies in the United Kingdom."

Rick Springman, Holtec's President of Global Clean Energy Opportunities responsible for Holtec Britain, said: "We are proud of our Holtec Britain organisation for securing regulatory Step 1 endorsement in record time. We are confident of our capability to deliver SMR-300 plants in numbers needed by the country. It helps that our SMR-300 plant is premised on the PWR technology with which Great Britain is well versed in its civilian as well as naval nuclear programme."

The SMR-300 is one of six SMR designs selected in October by Great British Nuclear on a shortlist for the UK's SMR selection competition and one of the five vendors to submit a bid by the 8 July deadline. The aim is for a final investment decision on two or three of the designs to be taken in 2029.

Holtec's plan for the UK includes the establishment of a heavy manufacturing plant in the country to build SMR-300 components mirroring the company's existing plants in the USA. Selection of the most suitable site for the manufacturing facility is underway.

The company said it is on track to begin the licensing and construction of two SMR-300 units at its Palisades nuclear power plant site in Michigan. It is aiming to file a construction permit application for the two Palisades SMRs in 2026 with the first SMR-300 plant targeted for mid-2030, subject to regulatory reviews and oversight.

Researched and written by World Nuclear News